1. Field of the Invention
The present invention relates to an image processing apparatus capable of performing density adjustment processing on image data, an image processing method, and a medium.
2. Description of the Related Art
A density adjustment technique has been used in outputting digital data generated by a computer using a printer or a multifunction peripheral (hereinafter referred to as MFP).
Two methods are currently used as such a technique. One is a uniform adjustment in which density is adjusted by changing a tilt based on a linear characteristic for each input color signal, and the other is an independent adjustment in which density is independently adjusted by overlapping adjacent density areas with respect to a plurality of density areas (refer to Japanese Patent Application Laid-Open No. 07-221986). The density adjustment method discussed in Japanese Patent Application Laid-Open No. 07-221986 is capable of independently adjusting density for each adjacent density area and an effective means for maintaining an adjustment effect in the vicinity of the adjacent density area.
In the above conventional technique, however, density adjustment by overlapping with adjacent density areas with respect to the plurality of density areas may invert output in the overlapped density area after the adjustment depending on an adjustment setting value. Such a phenomenon can prominently occur particularly in a monochrome machine and in a single color printing.
In the conventional technique discussed in Japanese Patent Application Laid-Open No. 07-221986, the output density value is kept constant in the overlapped density area to prevent density from being inversed in the overlapped area, however, this configuration causes a problem that gradation in a target density area is degraded and deteriorates the image quality.